Process of making paper-stock from cereal straw.



J. E- LAPPEN. PROCESS OF MAKING PAPEB STOCK FROM CEREAL STHAW, APPLICATION man APR. 2:. 1916.

1 ,236,723 Pi'ltGl'l'U-Pd Am 14;, 191?.

Jim

UNITED STATES PATENT OFFICE.

IAHES.E. 14mm, OF WINONA, MINNESOTA, ASSIGNOJR T0 WINQNA PULP & PAPER COMPANY, OF 'WINONA, MINNESOTA, A CORPORATION...

Specification of Letters Patent.

. Patente Aug, 14, 1917.

Application filed April 21, 1916. Serial No. 92,607,

To all whom it may concern:

Be it known that I, JAMES E. Lhnrnn, a citizen of the United States, residing at Winona, in. the county of Winona and rotate of Minnesota, have invented certhin new and useful Improvements in Processes of Making Paper-btockfrom Cereal Straw, of which the followin is a specification.

My invention re ates to improvements in the art of makin pa er stock, including socelled half-stoc 'rdm cereal straw, such as wheat, oats, barley, and the like.- In such straw the fibers are comparatively short and are bound together by the natural gums of theplant with varying degrees of strength in the different parts of the strew,----the fibers inthe stalk, for instance, holding together more tcnaciously than those in the chafi or the leaves: and. with the straw as it is taken from the field there is always more or less weed and other foreign matter, so that the length and severity of the treat-- ment necessary to remove the gums and separate the fibers in the different parts of the material will naturally wiry. It is important therefore that the process shall not be such as to destroy the fibers in the weaker parts while the more refractory parts are being reduced.

It has been customary l'icretoforc to cook the straw in open vats or rotary digostcrs. under no pressure other than atmospheric pressure, until the gummy constituents which bind the straw fibers together have been loosened up and the coloring matter released, and then to pour oil the gummy liquor, which has become brown from taking up this coloring matter, and empty the vessel of tho mushy cooked muss. But notwithstanding that the liquor is thus poured of! some of it will. always remain in the mass and not only give it color but form hard and lumpy parts, owiir to the reuniting'of the m with the lbers when the mass gets co (1 .or dry. It is therefore customary, after the mass has been cooked, to wash it in order more completely to remove the coiorin matter and gummy constituents, and t on to beat it in a beatin machine in order to break up the bar and lumpy parts so formed. But even when the stock is passed through the washing and beating apparatus, it will produce a paper which hard. slivers and particles of browncr color embedded therein, because of the incomplete rennivsl of the. gums and separation of the fibers. Besides, the Washing process is objectionable because a considerahle amount of the stock Will be wasl'ied away, and the heating is undesirehlo be cause it breaks up the fibers. 7 r

Sometimes also the fibrous mass has been treated at some stage of the process with allmlis or'other chemicals in the eil'ortto remove the gums. But with a stock of straw such as above described wherein the fibers in the different parts of the straw are bound together with varying degrees of strength, the fibers 'in the Weaker portions of the straw, such as the chntl and leaves, will. he opt to be destroyed by the treatment before the fibers in the stroi'iger parts, such as the stalks, have been fully dogummed and sop nrnted.

It is the object of this process to improve the method of treating the strdw by thonoughly removing the coloring matter and the gummy constituents that bind the fibers together while the cooked muss is stil worm end in the digester and without the use of chemicals, so as to prevent the gums and.

coloring matter from r'emzuningr in the wet mass and reuniting with the iln; .after they have once been softened itlltl separated therefrom, thereby melting urmvcesshry the subsequent washing and chemical treatment with its resultant loss of stock and the treating of the stock in n beating mnchinewith the umlesiruble breaking up of the long fibers which give strength to the paper made from it, and avoiding the waste" of fiber inherent in the chemical treatment of the stock.

in carrying out my improved process I first cookthe straw under pressureuntil the gummy constituents and coloring matto! have become loosened up and. washed out and then drive out the brown, gummy liquor by forcing water through the fibrous mass while the some is still heated and under pressure. While the. process not de pendent upon the pn rticulnr sort of mineratus used in carrying it out, yet l have found the apparatus illustrated in the uccompunving drawings. particularly suitable for the purpose.

In the drawings,

I Figure 1 is a view partly in side elevation, and partly in vertical section, of the digester in which I carry out the process; and

Fig. 2 is a top View of the same.

In the drawings, A represents the digester or boiler in which the straw is to be treated. Leading into the bottom of this digester at diametrically opposite points are two pipes 2, which are branches of a pipe 3 through which Water and steam or either water or steam canibc introduced into the digester, the water being supplied to the pipe 8 through a valved Water supply pipe 4, and. the steam through a valved steam pipe 5, both of which pipes lead. into a common union 6 in the pipe 3. In the pipes 4 and 5 are valves 7 and 8, respectively whereby to control the supply of water and. steam to the pipe 3, which. leads to the digester. I

At the top of the digester is a valved outlet pipe 9 which has two branch pipes 10 leading into the upper end of the digester at diametrically opposite points like the inlet pipes 2 at the bottom. In the top of the digester is a man-hole 11 through which the straw B can be loaded into the digester, and at the bottom is a similar man-hole 12 through which the stock can. be remcwed after it has been subjected to the treatment about to be described. When the apparatus is in use these man-holes are tightly sealed by means of covers or man-l1ole plates 1" so as to be steam tight and water tight.

hen the digester has been filled up with straw, warm water is introduced into the bottom of the digester through the pipe 3, while the valve 14 in the outlet pipe 9 is left open. The warm water obtained by opening the valve 7 in the water supply pi :e 4 and partly-opening the valve 8 in t e steam pipe 5, whereby the steam will heat the water in its passage to the digester. When the water has risen nearly to the top of the digester leaving an air space of from 12 to 18 inches above it the valve l-il. at the top is closed and the supply of water is shut off by closizixg the *alvc 7 while the cam valve 8 is opened-to turn the live seam full on. I prefer to heat the water before it enters the digestcr; otherwise the steam would condense and the watcr of con dcnsatlon might be so rnuch. as to fill the digcster and block the passage of the steam. I

The steam entering the digester will heat the water therein to the boiling point, and the steam and hot water will pass up and circulate through the mass of straw and cook" the same so as to soften and loosen up the malt-wring matter and gummy cons Hutsv thereof; This coolsiingg should cont to about three hours. Then the valve :1. the steam supply plpc 1S partly shut and water turnml on by opening the valve 7., the water being heated by the steam coming through the partly open valve 8. The valve in the pipe 9 at the top is then partly opened so as to let off steam and allow a circulation of the water and. steam through the digester while still maintaining a pressure therein. The brown liquor containing the gummy constituents, dirt, and colored matter will thus be forced out through the pipe 9 at the top by the water and steam entering at the bottom, while the contents of the digester are still under pressure.

This circulation is allowed to continue from three to twelve hours according to the color and quality of the stock that is dc- "sircd. The longer the circulation is continned, the more completely will the gums and coloring matter be washed or separated out. If the product desired is only halfstock so-called, wherein the fibers are only partly separated and degummed, the circulation need not be continued for more than the shorter period above named, but to reduce-it to full paper stock the circulation must be continued longer.

\Vhen the circulation has been carried far enough the valve 8 in the steam pipe is closed and the valve 7 opened to allow cold water to be forced into the bottom of the digestcr. This water will riscup through the mass and force the remainder of the hot gummy colored liquor out at thetop and wash the stock. It is important that this water should be cool, so that it will not mix with the warm gummy liquor in the digester, but will force this 1i uor bodily up and out through. the outlet pipe 9. As soon as the digester begins to get cool at the top the liquor will run clear showing that the lms and the coloring matter which has been. reed have been very completely forced out.- The mass 5 then ready to be removed from the digcstcl through the man hole 12 at the bot-' tom.

When the circulation has been continued long enough to form full paper stock the fibrous mass is so clean and free from gums and coloring matter and from the brown gummy liquor that it does not need any further waslaing, and the fibers are so sepvaratcd, and free from lumps and hard or unscparatcd particles that the mass does not need beating in the usual beating machine, but is ready for use as paper stock in'the paper making process, and the product is of uniform texture and will not become lumpy when formed. whereby the paper made from it will not be hard and brittle like the Old fashioned butchers wrapping paper, but will be soft, clear and By the pi nt process therefore I am onabled to client a very co .-to removal of the coloring mothers a nd. gammy constituents of the straw without the use of chemicals and without any loss of stock or breaking up of the long fibres which are so desirable in giving strength to the paper. While the process is particularly inteiwled for the treatment of cereal straw, it is equally applicable to any othcrkind of straw or fibrous material having gums or coloring matter to be removed.

By the term pressure as herein used I mean a pressure greater than atmospheric pressure. v

\Vhcn removed from the digester in the condition of half-stock, that is before all thefihcrs have been dcgummcd and separated, the product will form an excellent heat insulating product because of its light weight and spongy texture due largely to the very complete removal of the gummy liquor and hccause of the intimate admixture. and intertanglcment of the finer mass of more, or less completely degummed and separated tihcrs with the coarser unseparated particles, this admixture being possible because the treatment has been such as not to destroy these fine fibers.

1. The herein (lescrihed process of making paper stock from straw containing a gummy tconstitucnt which consists in cooking the st raiwinj water and under pressure to loosen up the gummy constituent and-then forcing out the gummy liquor fifrmedin cooking while the same is still warm and under pressure.

.2. The herein described process of making paper stock from straw containing a gummy constituent which consists in cooking the straw until the gummy constituent has he,- (:(mw. loosened up, and their forcing cold water through the cooked mass while the same is under pressure and still warm, whereby to drive. ofi' the gummy liquor.

3. The herein described process of making paper stock lrom straw containing a gummy constituent which consists in cooking the straw in water under pressure to loosen up the gummy constituent and then forcing cold water through the cooked mass while the same. is still heated and under pressure, where-by to drive 011' the gummy liquor.

4. The herein described process of making a paper stock from straw containing a gummy constituent which consists in first cooking the straw in watc and under pressure to loosen up the gummy constituent, then forc ing warm water through the mass While the same is under pressure to drive ofi the gummy matter thus loosened up and then forcing cold water through the mass while same is under pressure and still warm, wherchy to wash out the gummy liquor without allowing it to become mixed with said cold water. 7

5. A tihrous product of the herein descrihcd process formed by first cooking cereal straw in water and under pressure to loosen up the/gummy constituents thereof, then forcing warm water through the mass while the same is still warm and under pressure to wash out the gummy matter thus loosened up, and then driving: off the gummy liquor while the same is still warm, substan tially as descrihedv In testimony whereof I afiix my signature in presence 0" two nitnesscs.

JAMFS F. TAPPEN. \Vitncsscs ll Swassou,

Ahrmu: l. Lo'rnuor. 

